Coil device

ABSTRACT

A coil device of solenoid type includes a coil portion having a bobbin and a conductive wire wound around the bobbin, a housing for accommodating the coil portion, and at least one fastener for fastening the bobbin and the housing. The conductive wire includes a plurality of extending portions extending along a wound wire direction on the bobbin and having gaps in a winding axis direction. The fastener is provided between the plurality of extending portions and is obliquely disposed with respect to a plane orthogonal to the winding axis direction.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation application of International Application No. PCT/JP/2015/061154, filed Apr. 9, 2015, which claims priority to Japanese Patent Application No. 2014-105907, filed on May 22, 2014. The contents of these applications are incorporated herein by reference in their entirety.

TECHNICAL FIELD

The present disclosure relates to a coil device.

BACKGROUND ART

A wireless power transfer system includes a power transmission coil device and a power reception coil device, and implements wireless power transfer using electromagnetic induction, magnetic resonance, etc. between coils. Each of the coil devices has a coil and ferrite therein. The coil device is surrounded by a housing. For example, the housing includes a protective cover and an aluminum plate. For example, the wireless power transfer system is applied to a power feeding system of an electric vehicle. In this case, the power reception coil device is installed in the vehicle.

Technologies disclosed in Patent Literatures 1, 2, and 3 are known. In an apparatus disclosed in Patent Literature 1, an in-vehicle transducer corresponding to a power reception coil device is installed in a vehicle (chassis). Alternatively, the in-vehicle transducer is installed to protrude downward on a lower surface of a vehicle body. In an apparatus disclosed in Patent Literature 2, a bobbin that supports a secondary self-resonant coil corresponding to a power reception coil is attached to a vehicle by a fixing member connected to a flange portion thereof.

In an apparatus disclosed in Patent Literature 3, an aluminum substrate of a power reception unit is fixed to a lower portion of a moving body by a non-magnetic bolt through a bolt hole. An aluminum substrate of a power feeding unit (power transmitter) is fixed to a road surface, etc. by a non-magnetic bolt through a bolt hole. A protective cover made of polycarbonate is fixed to the substrate by a non-magnetic bolt through a bolt hole. A spacer is provided between the protective cover and an insulating plate, and strength of the protective cover is increased by the spacer.

CITATION LIST Patent Literature

Patent Literature 1: Japanese Unexamined Patent Publication No. 2013-153132

Patent Literature 2: Japanese Unexamined Patent Publication No. 2010-87353

Patent Literature 3: Japanese Unexamined Patent Publication No. 2008-120239

SUMMARY Technical Problem

In a solenoid coil disclosed in Patent Literature 1, a bobbin around which a conductive wire is wound (a ferrite housing portion in the apparatus of Patent Literature 1) is disposed to extend in a flat plate shape between a protective cover and an aluminum plate. A plurality of slot-shaped grooves is formed in the bobbin, and the conductive wire is disposed in the grooves. In this configuration, the conductive wire wound around the bobbin has a plurality of parallel linear portions on each of a surface side and a rear surface side of the bobbin. Therefore, the conductive wire is present over the entire area of the bobbin disposed between the protective cover and the aluminum plate.

A spacer disclosed in Patent Literature 3 is known to be provided to increase strength of a housing. However, there is difficulty in applying the spacer to a solenoid coil in which a conductive wire is present over the entire area of a bobbin. Increasing strength of the housing is an issue in a coil device that employs the solenoid coil.

An object of the present disclosure is to provide a coil device of solenoid type capable of increasing strength of a housing.

Solution to Problem

A coil device according to an aspect of the present disclosure is a coil device of solenoid type including a coil portion having a bobbin and a conductive wire wound around the bobbin, a housing for accommodating the coil portion, and at least one fastener for fastening the bobbin and the housing, wherein the conductive wire includes a plurality of extending portions extending along a wound wire direction on the bobbin and having gaps in a winding axis direction, and the fastener is provided between the plurality of extending portions, and is obliquely disposed with respect to a plane orthogonal to the winding axis direction.

According to this coil device, the housing accommodates the coil portion that includes the bobbin. The at least one fastener is provided between the plurality of extending portions extending in the wound wire direction on the bobbin. The bobbin and the housing are fastened by the fastener. Since the fastener is obliquely disposed with respect to the plane orthogonal to the winding axis direction, it is easy to avoid interfering in the extending portions of the conductive wire by the fastener. In other words, a degree of freedom is increased when the fastener is provided. Therefore, strength of the housing may be increased in the coil device of solenoid type.

In some embodiments, the coil portion further includes a magnetic member disposed inside the bobbin. In this case, power efficiency is increased.

In some embodiments, the housing includes a first housing member facing a first surface of the coil portion having a flat plate shape, and a second housing member fixed to the first housing member to face a second surface on an opposite side from the first surface. In this case, strength of the housing may be increased by fastening the bobbin and at least one of the first housing member and the second housing member by the fastener.

In some embodiments, the bobbin includes a first winding plate disposed between the first housing member and the magnetic member, and a second winding plate disposed between the second housing member and the magnetic member, and the fastener penetrates through the magnetic member and fastens the first winding plate and the second winding plate. In this case, the magnetic member is provided between the first housing member and the second housing member. The fastener penetrates through the magnetic member, and the first winding plate and the second winding plate are fastened, and thus the housing is more strongly fixed to the bobbin.

In some embodiments, a hole portion is provided in the magnetic member, one of the first winding plate and the second winding plate includes a protrusion protruding to an inside of the hole portion, and the fastener penetrates through the protrusion to fasten the first winding plate and the second winding plate. In this case, the fastener penetrates through the protrusion disposed inside the hole portion of the magnetic member to fasten the first winding plate and the second winding plate. The first winding plate and the second winding plate are more strongly fastened. The magnetic member is sandwiched between and held by the first winding plate and the second winding plate. The magnetic member may be fragile. However, according to the above configuration, strength of the magnetic member may be increased.

In some embodiments, the fastener includes a flange portion contacting the first winding plate from a side of the first housing member, and the first housing member is supported by the coil portion through the flange portion. In this case, since the first housing member is supported by the coil portion, the first housing member may be prevented from being bent around the fastener.

In some embodiments, the fastener penetrates through the housing. Fastening using the fastener is performed from the outside of the housing, and thus the fastener may be reliably and easily provided.

In some embodiments, the fastener includes a first combined member integrally provided in the first housing member to protrude toward the second housing member, and a second combined member integrally provided in the second housing member to protrude toward the first housing member, and at least one of the first combined member and the second combined member is disposed inside the coil portion, and the first combined member and the second combined member are combined together. In this case, the fastener does not penetrate through the housing, and thus a seal around the fastener is not needed.

In some embodiments, the coil portion includes an equal portion in which a gap between extending portions adjacent to each other in the winding axis direction is equal to a gap between other extending portions, and the fastener is provided in the equal portion. In this case, a pitch of the conductive wire in the equal portion of the coil portion is equal to a pitch in another portion, and thus influence on a magnetic field may be made as small as possible. The fastener is obliquely disposed with respect to the plane orthogonal to the winding axis direction. Thus, even when the fastener is provided in the equal portion, interference in the conductive wire may be easily avoided.

In some embodiments, the fastener is provided in a central region of the bobbin in the wound wire direction and the winding axis direction. In this case, strength of the housing is increased at a position corresponding to the central region of the bobbin. The housing is relatively easily bent at the position corresponding to the central region of the bobbin. Therefore, strength of the housing is further improved.

In some embodiments, the fastener is provided in a central region of the housing in the wound wire direction and the winding axis direction. In this case, strength of the housing is increased at a position corresponding to the central region of the housing. The housing is relatively easily bent in the central region. Therefore, strength of the housing is further improved.

In some embodiments, the fastener is provided in a region in which a decrease in power efficiency due to provision of the fastener is less than or equal to 0.1%. In this case, an influence on power efficiency by the fastener may be made as small as possible.

In some embodiments, the fastener is provided in a region in which a magnetic flux density in the coil portion is lower than a magnetic flux density in another region. In this case, an influence on a magnetic flux by the fastener may be made as small as possible.

In some embodiments, the at least one fastener includes a plurality of fasteners, and the plurality of fasteners are arranged along the winding axis direction.

In some embodiments, the at least one fastener includes a plurality of fasteners, and the plurality of fasteners are arranged along the wound wire direction.

Effects

According to some embodiments of the present disclosure, strength of a housing may be increased in a coil device of solenoid type.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a diagram illustrating an application example of a coil device according to an embodiment of the present disclosure.

FIG. 2 is a perspective view illustrating the coil device according to the embodiment of the present disclosure.

FIG. 3A is a cross-sectional view schematically illustrating a portion in which a fastener is provided, and FIG. 3B is a diagram describing a positional relationship of a conductive wire of FIG. 3A.

FIG. 4 is a cross-sectional view illustrating a portion around the fastener of FIG. 2.

FIG. 5 is a plan view illustrating central regions of a housing and a bobbin.

FIG. 6A is a plan view illustrating an installation position of the fastener when a magnetic flux density or power efficiency is considered, and FIG. 6B is a plan view illustrating an installation position of the fastener when strength is considered.

FIG. 7 is a plan view illustrating a region in which a region illustrated in FIG. 6A overlaps a region illustrated in FIG. 6B.

FIG. 8 is a cross-sectional view schematically illustrating a portion in which a fastener is provided in another embodiment.

FIG. 9 is a cross-sectional view schematically illustrating a portion in which a fastener is provided in another embodiment.

FIG. 10 is a cross-sectional view schematically illustrating a portion in which a fastener is provided in another embodiment.

FIG. 11 is a cross-sectional view schematically illustrating a portion in which a fastener is provided in another embodiment.

FIG. 12 is a cross-sectional view schematically illustrating a key structure of a housing in another embodiment.

FIG. 13A is a plan view illustrating a mode in which two fasteners are arranged in a winding axis direction, and FIG. 13B is a plan view illustrating a mode in which two fasteners are arranged in a wound wire direction.

FIG. 14 is a cross-sectional view describing a case in which a fastener is provided in a conventional solenoid coil.

DESCRIPTION OF EMBODIMENTS

Hereinafter, embodiments of the present disclosure will be described with reference to drawings. The same reference numeral will be applied to the same component in description of the drawings, and repeated description will be omitted.

A wireless power transfer system 1 to which a coil device of the present embodiment is applied will be described with reference to FIG. 1. The wireless power transfer system 1 is a system for feeding power from a power transmitter 2 to a power receiver 3. For example, the power transmitter 2 and the power receiver 3 are separated from each other in a vertical direction. For example, the power transmitter 2 is installed in a parking lot, etc. For example, the power receiver 3 is installed in an electric vehicle EV. The wireless power transfer system 1 is configured to feed power to the EV arriving at the parking lot, etc. using a magnetic resonance scheme, an electromagnetic induction scheme, etc.

The power transmitter 2 includes a power transmission coil device 4 for wireless power transfer provided to protrude upward from a road surface of the parking lot, etc. For example, the power transmission coil device 4 has a shape of a flat rectangular parallelepiped or frustum. The power transmitter 2 generates desired AC power from a DC power source or an AC power source to send the generated AC power to the power receiver 3, and further includes a controller, an inverter, etc. (not illustrated). For example, the power receiver 3 includes a power reception coil device 5 for wireless power transfer attached to a bottom surface of a vehicle body (chassis, etc.) of an EV to face the power transmission coil device 4. For example, the power reception coil device 5 has a shape of a flat rectangular parallelepiped or frustum. The power receiver 3 receives power from the power transmitter 2 to feed power to a load (e.g., a battery), and further includes a controller, a rectifier, etc. (not illustrated). Hereinafter, the power transmission coil device 4 and the power reception coil device 5 will be referred to as a coil device 4 and a coil device 5, respectively.

The coil device 5 will be described with reference to FIG. 1 and FIG. 2. The coil device 5 generates an induced current when a magnetic flux generated by the power transmission coil device 4 interlinks with the coil device 5. The coil device 5 corresponds to a solenoid type. The coil device 5 includes a flat plate-shaped coil portion C that generates an induced current and a housing 10 that accommodates the coil portion C.

For example, the housing 10, which has a shape of a flat rectangular parallelepiped, includes a base (second housing member) 12 and a protective cover (first housing member) 11 that forms an accommodation space between the protective cover 11 and the base 12 (see FIG. 3A and FIG. 3B). The protective cover 11 faces a surface (first surface) C1 of the coil portion C. The base 12 faces a rear surface (second surface on the opposite side from the first surface) C2 of the coil portion C. When the coil device 5 is installed in the EV, for example, the base 12 is fixed to the vehicle body side. The protective cover 11 faces the coil device 4. That is, the base 12 is disposed above the coil portion C, and the protective cover 11 is disposed below the coil portion C while the coil device 5 is installed in the EV. For example, the base 12 and the protective cover 11 are made of resin. Alternatively, the base 12, which does not face the coil device 4, may be formed using a non-magnetic or conductive material (e.g., aluminum).

The base 12 is a portion fixed to the vehicle body of the EV. For example, the base 12 is fixed to the vehicle body by four screw members 15 at four corner portions. The base 12, which has a rectangular shape, includes a rectangular-shaped accommodating depression 12 a slightly smaller than an external form thereof. The coil portion C is accommodated in the accommodating depression 12 a, and is fixed to the base 12 by a screw member such as a screw. An insulation sheet may be inserted between the coil portion C and the base 12.

For example, the protective cover 11, which has a rectangular shape, is fixed to the base 12 by four screw members 14 through four screw holes 13 at edges of the base 12. A gap G (see FIG. 4) is formed between the protective cover 11 and the coil portion C substantially over the entire region of the surface C1 of the coil portion C. A fastener 16 described below is provided at a center of the protective cover 11. A seat 11 b and a through-hole 11 c for providing the fastener 16 are formed in the protective cover 11. The gap G extends between the protective cover 11 and the coil portion C in a region except for a portion in which the through-hole 11 c is formed.

As illustrated in FIG. 2, FIG. 3A and FIG. 3B, the coil portion C includes a conductive wire 30 corresponding to a litz wire, and a flat plate-shaped bobbin 20 around which the conductive wire 30 is wound. The bobbin 20 includes a rectangular-shaped first winding plate (first winding plate) 21 disposed on the surface C1 side, and a rectangular-shaped second winding plate (second winding plate) 22 disposed on the rear surface C2 side. The first winding plate 21 and the second winding plate 22 are formed using the same material (e.g., a polyphenylene sulfide resin).

A ferrite plate (magnetic member) 23 is disposed between the first winding plate 21 and the second winding plate 22. That is, the ferrite plate 23 is disposed inside the bobbin 20. In plan view, a shape and a size of the ferrite plate 23 are substantially equal to or smaller than shapes and sizes of the first winding plate 21 and the second winding plate 22. The ferrite plate 23 is sandwiched between and held by the first winding plate 21 and the second winding plate 22. The first winding plate 21 is disposed between the ferrite plate 23 and the protective cover 11. The second winding plate 22 is disposed between the ferrite plate 23 and the base 12.

The magnetic member is not restricted to the ferrite plate. The magnetic member may be made of another magnetic material (e.g., a silicon steel plate, an amorphous magnetic alloy, and a magnet). In particular, the magnetic member may be made of a soft magnetic material (e.g., ferrite, a silicon steel plate, and an amorphous magnetic alloy) in terms of improving power efficiency. In addition, a component disposed inside the bobbin 20 is not restricted to the magnetic member, and may correspond to a reinforcing material that fills a portion or a whole of a cavity inside the bobbin 20 to ensure strength of the coil portion C. Further, the present invention is not limited to a case in which the magnetic member or the reinforcing material is disposed inside the bobbin 20. The coil portion C may be an air-core coil in which the inside of the bobbin 20 remains as a cavity. Power efficiency refers to a ratio of power at a certain place inside the power receiver 3 to power at a certain place inside the power transmitter 2. For example, power efficiency refers a ratio of power of an output of a rectifier of the power receiver 3 to power of an input of an inverter of the power transmitter 2. Herein, the inverter of the power transmitter 2 generates AC power, which is transmitted from the power transmitter 2 to the power receiver 3, from DC power (power obtained by rectifying an output from the DC power source or an output from the AC power source, etc.). The rectifier of the power receiver 3 converts AC power from the power transmitter 2 into DC power (e.g., power input to the battery).

For example, a plurality of groove portions 21 b extending in a long-side direction of the coil portion C is formed in the first winding plate 21. The plurality of groove portions 21 b is parallel to each other, and is formed at equal intervals. A cross-sectional shape of the plurality of groove portions 21 b perpendicular to the long-side direction corresponds to a rectangular shape in which one side on the protective cover 11 side is open. The groove portion 21 b is recessed with respect to a surface 21 a of the first winding plate 21, and has a predetermined depth.

For example, a plurality of groove portions 22 b extending in the long-side direction of the coil portion C is formed in the second winding plate 22. The plurality of groove portions 22 b is parallel to each other, and is formed at equal intervals. A cross-sectional shape of the plurality of groove portions 22 b perpendicular to the long-side direction corresponds to a rectangular shape in which one side on the base 12 side is open. The groove portion 22 b is recessed with respect to a surface 22 a of the second winding plate 22, and has a predetermined depth.

The first winding plate 21, the ferrite plate 23, and the second winding plate 22 described above are integrated with one another, and are wound with the conductive wire 30. More specifically, the conductive wire 30 is disposed inside the groove portion 21 b and the groove portion 22 b. As illustrated in FIG. 3A and FIG. 3B, in the coil portion C, a position at which the groove portion 21 b is provided and a position at which the surface 22 a is provided are different from each other in a short-side direction of the coil portion C. In other words, the groove portion 21 b and the groove portion 22 b are not aligned in the vertical direction (a direction perpendicular to the surface C1 of the coil portion C, that is, a plate thickness direction of the first winding plate 21 and the second winding plate 22).

According to the above configuration, the conductive wire 30 wound around the bobbin 20 includes a plurality of surface-side extending portions 31 extending on the first winding plate 21 and a plurality of rear surface-side extending portions 32 extending on the second winding plate 22. The long-side direction of the coil portion C is equal to a wound wire direction of the conductive wire 30, and the short-side direction of the coil portion C is equal to a winding axis direction of the conductive wire 30. The wound wire direction and the winding axis direction are orthogonal to (intersect with) each other. The conductive wire 30 extends in a direction which is inclined with respect to the vertical direction on an end surface of the bobbin 20 in the wound wire direction. The respective surface-side extending portions 31 and the respective rear surface-side extending portions 32 are not aligned in the vertical direction. The surface-side extending portions 31 and the rear surface-side extending portions 32 are provided in a vertically diagonal shape (in zigzag) when viewed in the wound wire direction (see FIG. 3A and FIG. 3B). When the conductive wire 30 is disposed as described above, portions of the conductive wire 30 are separated from each other as much as possible, and an insulation distance is ensured in the coil portion C.

A more detailed description will be given of the surface-side extending portions 31 and the rear surface-side extending portions 32 with reference to FIG. 3A, FIG. 3B and FIG. 4. The plurality of surface-side extending portions 31 extending along the wound wire direction have linear shapes, and are parallel to each other. As described above, the plurality of groove portions 21 b is formed at equal intervals. As illustrated in FIG. 3B, a distance between centers, that is, a pitch of two surface-side extending portions 31 and 31 is a pitch P1. The pitch P1 is uniform in the plurality of surface-side extending portions 31 formed on the first winding plate 21. When distances between the surface-side extending portions 31 are compared, pitches may be used for the comparison as described above, or gaps between the surface-side extending portions 31 may be used for the comparison as illustrated in FIG. 4. A gap between the surface-side extending portions 31 and 31, that is, a distance between two inner end surfaces facing each other in the winding axis direction is a gap D1. The gap D1 is uniform in the plurality of surface-side extending portions 31 formed on the first winding plate 21.

The coil portion C includes an equal portion 35 in which a gap D1 between surface-side extending portions 31 and 31 adjacent to each other in the winding axis direction is equal to a gap D1 between other surface-side extending portions 31 and 31. In the coil portion C, a gap between arbitrary surface-side extending portions 31 and 31 adjacent to each other among the plurality of surface-side extending portions 31 is the gap D1 which is equal to a gap between other portions. A plurality of equal portions 35 is formed on the first winding plate 21 of the coil portion C.

The plurality of rear surface-side extending portions 32 extending along the wound wire direction have linear shapes, and are parallel to each other. As described above, the plurality of groove portions 22 b is formed at equal intervals. As illustrated in FIG. 3B, a distance between centers, that is, a pitch of two rear surface-side extending portions 32 and 32 is a pitch P1. The pitch P1 is uniform in the plurality of rear surface-side extending portions 32 formed on the second winding plate 22. A gap between the rear surface-side extending portions 32 and 32, that is, a distance between two inner end surfaces facing each other in the winding axis direction is a gap D1. The gap D1 is uniform in the plurality of rear surface-side extending portions 32 formed on the second winding plate 22.

The coil portion C includes an equal portion 35 in which a gap D1 between rear surface-side extending portions 32 and 32 adjacent to each other in the winding axis direction is equal to a gap D1 between other rear surface-side extending portions 32 and 32. In the coil portion C, a gap between arbitrary rear surface-side extending portions 32 and 32 adjacent to each other among the plurality of rear surface-side extending portions 32 is the gap D1 which is equal to a gap between other portions. A plurality of equal portions 35 is formed on the second winding plate 22 of the coil portion C.

As illustrated in FIG. 2 to FIG. 5, the fastener 16 capable of increasing strength of the protective cover 11 is provided in the equal portion 35 in which a pitch of the conductive wire 30 is uniform. A hole portion 26 in which the fastener 16 is provided is obliquely formed in the bobbin 20 of the coil portion C to pass between the surface-side extending portions 31 and 31 and between the rear surface-side extending portions 32 and 32. According to this arrangement, interference in the conductive wire 30 by the fastener 16 is avoided.

As illustrated in FIG. 3B, symmetry between the surface-side extending portions 31 and the rear surface-side extending portion 32 is maintained in the coil portion C. The rear surface-side extending portion 32 is positioned at a center of the surface-side extending portions 31 and 31 adjacent to each other in the winding axis direction. The surface-side extending portion 31 is positioned at a center of the rear surface-side extending portions 32 and 32 adjacent to each other in the winding axis direction. A relationship of a vertically diagonal shape (a zigzag positional relationship) is maintained in the coil portion C.

A detailed description will be given of the fastener 16 with reference to FIG. 4 and FIG. 5. As illustrated in FIG. 5, the fastener 16 is provided in a first central region A1 which is a central region of the bobbin 20 in the wound wire direction and the winding axis direction. In other words, the fastener 16 is provided at an intersection point of first diagonal lines L1 and L1, that is, a central point of the bobbin 20.

The fastener 16 may be provided inside the first central region A1, a center of which corresponds to the intersection point of first diagonal lines L1 and L1 of the bobbin 20. The fastener 16 may be provided in a second central region A2 which is a central region of the housing 10 (that is, the protective cover 11 or the base 12) in the wound wire direction and the winding axis direction. In other words, the fastener 16 may be provided at an intersection point of second diagonal lines L2 and L2, that is, a central point of the base 12, or may be provided inside the second central region A2, a center of which corresponds to the intersection point.

As illustrated in FIG. 4, the fastener 16 is obliquely disposed with respect to a plane perpendicular to the winding axis direction. The plane perpendicular to the winding axis direction refers to a virtual plane that extends in the wound wire direction and the vertical direction (that is, the plate thickness direction of the first winding plate 21 and the second winding plate 22). In the present embodiment, the fastener 16 forms an angle with respect to the vertical direction, and forms an acute angle or an obtuse angle (an angle other than 90°) with respect to the winding axis direction. The fastener 16 is disposed in a direction orthogonal to the wound wire direction.

The fastener 16 penetrates through the protective cover 11, the first winding plate 21, the ferrite plate 23, and the second winding plate 22. A distal end portion 17 c of the fastener 16 does not penetrate through the base 12, and terminates inside the base 12. More specifically, the fastener 16 includes a cylindrical member 18 provided to penetrate through the first winding plate 21 and the second winding plate 22, a cylindrical member 19 provided to penetrate through the protective cover 11, and a screw member 17 disposed inside the cylindrical member 18 and the cylindrical member 19. The cylindrical member 18, the cylindrical member 19, and the screw member 17 are all made of non-magnetic metal. However, a magnetic material may be used. The cylindrical member 18 is fixed to at least one of the first winding plate 21 and the second winding plate 22. The cylindrical member 19 is fixed to the protective cover 11. The fastener 16 strongly fastens the protective cover 11, the first winding plate 21, the ferrite plate 23, the second winding plate 22, and the base 12 through the cylindrical members 18 and 19 using the screw member 17. In addition, when the fastener 16 is made of a material having a thermal conductivity, a portion of heat of the ferrite plate 23 heated by wireless power transfer is successively transferred to a protrusion 22 c and the fastener 16, and is released to the outside from a distal end portion 17 c and the cylindrical member 19. In particular, when the fastener 16 is made of a material having a high thermal conductivity (e.g., metal), heat release effect is increased.

For example, a circular hole portion 23 a is provided at a position corresponding to the fastener 16 in the ferrite plate 23. The second winding plate 22 includes the protrusion 22 c which has a cylindrical shape and protrudes to the inside of the hole portion 23 a. The hole portion 23 a may be a rectangle. A circular through-hole 22 d that penetrates through the second winding plate 22 in a thickness direction is provided at a center of the protrusion 22 c. A through-hole 21 c that communicates with the through-hole 22 d is formed in the first winding plate 21. The protrusion 22 c of the second winding plate 22 is disposed inside the hole portion 23 a of the ferrite plate 23. A surface of the protrusion 22 c contacts the first winding plate 21.

The cylindrical member 18 includes a flange portion 18 a contacting the first winding plate 21 from the protective cover 11 side, a first cylindrical portion 18 b formed on a distal end side of the flange portion 18 a and disposed inside the through-hole 21 c of the first winding plate 21, and a second cylindrical portion 18 c formed on a distal end side of the first cylindrical portion 18 b and disposed inside the through-hole 22 d of the second winding plate 22. The flange portion 18 a, which has a disc shape, is provided to be flush with an end surface 11 a of the protective cover 11. The flange portion 18 a, the first cylindrical portion 18 b, and the second cylindrical portion 18 c are integrally formed. The first cylindrical portion 18 b and the second cylindrical portion 18 c may be formed as separate bodies. The cylindrical member 19 is disposed inside a through-hole 11 c formed in a seat 11 b, and protrudes from the protective cover 11.

The screw member 17 includes a head portion 17 a disposed on the protective cover 11 side, a shaft portion 17 b formed on a distal end side of the head portion 17 a to penetrate through the protective cover 11, the first winding plate 21, the ferrite plate 23, and the second winding plate 22, and a distal end portion 17 c formed on a distal end side of the shaft portion 17 b and screwed to the base 12. The shaft portion 17 b is disposed inside the first cylindrical portion 18 b and the second cylindrical portion 18 c. A male screw is formed in the shaft portion 17 b and the distal end portion 17 c. The screw member 17 penetrates through the first winding plate 21 and the protrusion 22 c of the second winding plate 22 to fasten the first winding plate 21, the second winding plate 22, and the base 12. A female screw, to which the shaft portion 17 b of the screw member 17 can be screwed, may or may not be formed in the first cylindrical portion 18 b and the second cylindrical portion 18 c.

The head portion 17 a protrudes from the end surface 11 a of the protective cover 11. The seat of the protective cover 11 may be formed to be recessed from the end surface 11 a of the protective cover 11, and the head portion 17 a may be accommodated in the recessed portion of the seat. When this configuration is employed, the head portion 17 a of the screw member 17 is positioned on the base 12 side from the end surface 11 a of the protective cover 11. Therefore, a position of a lowermost end (that is, a minimum height) of the coil device 5 may be prevented from being lowered by the fastener 16. In this way, it is possible to avoid touching an object by the head portion 17 a when the EV is driven or stopped.

The hole portion 26 of the coil portion C described above (see FIG. 2) includes the through-hole 21 c, the hole portion 23 a, and the through-hole 22 d. A seal member is appropriately provided between the protective cover 11 and the flange portion 18 a. The seat 11 b of the protective cover 11 protruding to the coil portion C side is fixed to the flange portion 18 a by applying pressure through the seal member. The protective cover 11 is supported by the coil portion C through the flange portion 18 a.

In the above configuration, the through-hole 11 c of the protective cover 11, the through-hole 21 c of the first winding plate 21, and the through-hole 22 d of the second winding plate 22 are coaxially formed. An axial line thereof obliquely extends with respect to the plane perpendicular to the winding axis direction. The cylindrical member 19 and the cylindrical member 18 (the first cylindrical portion 18 b and the second cylindrical portion 18 c) are coaxially disposed. An axial line thereof is equal to the axial line of the through-hole 11 c, the through-hole 21 c, and the through-hole 22 d, and obliquely extends with respect to the plane perpendicular to the winding axis direction. The shaft portion 17 b and the distal end portion 17 c of the screw member 17 are obliquely disposed with respect to the plane perpendicular to the winding axis direction. An angle of inclination of the screw member 17 may be appropriately changed according to respective positions of the surface-side extending portions 31 and the rear surface-side extending portions 32.

The cylindrical member 19, the cylindrical member 18, and the screw member 17 are obliquely disposed by passing between the surface-side extending portions 31 and 31 and between the rear surface-side extending portions 32 and 32. In other words, the fastener 16 is obliquely provided to avoid interference in the surface-side extending portions 31 and the rear surface-side extending portions 32 in the equal portion 35 in which the gap between the surface-side extending portions 31 and 31 is equal to a gap between other portions.

When fastening is performed using the fastener 16, the second winding plate 22 in which the through-hole 22 d is provided, the ferrite plate 23 in which the hole portion 23 a is provided, and the first winding plate 21 in which the through-hole 21 c is provided are superposed. For example, the cylindrical member 18 is fixed to the first winding plate 21 and the second winding plate 22, and the first winding plate 21, the ferrite plate 23, and the second winding plate 22 are connected to one another. Subsequently, the seat 11 b of the protective cover 11 is superposed on the flange portion 18 a of the cylindrical member 18. When the screw member 17 is screwed in the base 12, the protective cover 11 is fastened to the first winding plate 21, the ferrite plate 23, and the second winding plate 22. The flange portion 18 a is pressed against the first winding plate 21 through the cylindrical member 19. The flange portion 18 a immobilizes the first winding plate 21 on the base 12 side. In this way, the first winding plate 21 is pressed against the second winding plate 22, and the ferrite plate 23 sandwiched between the first winding plate 21 and the second winding plate 22 is fixed. The protective cover 11 is supported by the base 12 and the coil portion C (bobbin 20) through the flange portion 18 a of the fastener 16.

According to the coil device 5 of the present embodiment, the housing 10 is accommodated in the coil portion C that includes the bobbin 20 and the ferrite plate 23. The fastener 16 is provided between the plurality of surface-side extending portions 31 and rear surface-side extending portions 32 extending in the wound wire direction on the bobbin 20. The bobbin 20 and the housing 10 are fastened by the fastener 16. Since the fastener 16 is obliquely provided with respect to the plane orthogonal to the winding axis direction, it is easy to avoid interfering in the surface-side extending portions 31 and the rear surface-side extending portions 32 of the conductive wire 30 by the fastener 16. In other words, a degree of freedom is increased when the fastener 16 is provided. Therefore, strength of the housing 10 is increased in the coil device 5 of solenoid type.

The housing 10 includes the protective cover 11 and the base 12. Strength of the housing 10 is increased by fastening the bobbin 20 and both the protective cover 11 and the base 12 using the fastener 16.

The ferrite plate 23 is provided between the protective cover 11 and the base 12. The fastener 16 penetrates the ferrite plate 23 to fasten the protective cover 11 and the base 12. Therefore, the housing 10 is more strongly fixed to the bobbin 20. Further, movement of the ferrite plate 23 in the wound wire direction and the winding axis direction is regulated.

The fastener 16 penetrates through the protrusion 22 c disposed inside the hole portion 23 a of the ferrite plate 23 to fasten the first winding plate 21 and the second winding plate 22. The first winding plate 21 and the second winding plate 22 are more strongly fastened. The ferrite plate 23 does not touch the fastener 16, and is indirectly fixed by the fastener 16. The ferrite plate 23 is sandwiched between and held by the first winding plate 21 and the second winding plate 22. In general, the ferrite plate 23 may be fragile. However, according to the above-described configuration, strength of the ferrite plate 23 is increased.

The protective cover 11 is supported by the coil portion C through the flange portion 18 a of the cylindrical member 18. The protective cover 11 does not touch the first winding plate 21 of the coil portion C, and touches the flange portion 18 a. Therefore, the first winding plate 21 is protected. The gap G is formed between the between the protective cover 11 and the coil portion C. However, a portion of the protective cover 11 (specifically, the seat 11 b) protrudes, and the protective cover 11 is supported by the coil portion C through the protruding portion. Therefore, the protective cover 11 may be reliably prevented from being bent around the fastener.

Since the fastener 16 penetrates through the housing 10, fastening using the fastener 16 may be easily performed from the outside of the housing 10. Therefore, the fastener 16 may be reliably and easily provided.

A pitch of the conductive wire in the equal portion 35 of the coil portion C is equal to a pitch in another portion. Thus, a variation in magnetic field distribution generated by the coil portion C may be made as small as possible when compared to a case in which the fastener 16 is not provided. The fastener 16 is obliquely disposed with respect to the plane orthogonal to the winding axis direction. Thus, even when the fastener 16 is provided in the equal portion 35, interference in the conductive wire 30 may be easily avoided.

Since the fastener 16 is provided in the first central region A1 of the bobbin 20 in the wound wire direction and the winding axis direction, strength of the housing 10 is increased at a position corresponding to the first central region A1 of the bobbin 20. When the fastener 16 is not provided, the housing 10 is relatively easily bent at a position corresponding to the second central region A2 of the bobbin 20. Strength of housing 10 is further improved by the fastener 16.

Even when the fastener 16 is provided in the second central region A2 of the housing 10 in the wound wire direction and the winding axis direction, strength of the housing 10 is increased at a position corresponding to the second central region A2 of the housing 10. When the fastener 16 is not provided, the housing 10 is relatively easily bent in the second central region A2. Strength of housing 10 is further improved by the fastener 16.

The coil device 5 has advantageous effect in contrast with the above respective conventional art documents. In the above Patent Literature 1, there is no examination of a scheme of attaching the power reception coil device to the outside of the vehicle. When the power reception coil device is installed inside the vehicle, the power reception coil device is supported by the chassis. However, it is unclear how to suspend the power reception coil device when the power reception coil device is installed to be exposed to the outside of the chassis of the vehicle. In general, as a distance between the power transmission coil device and the power reception coil device decreases, transmitting efficiency increases. Thus, there is a great need to attach the power reception coil device to the outside of the chassis of the vehicle. In this regard, according to the coil device 5 of the present embodiment, the base 12 is fixed to the outside of the chassis. When the protective cover 11 facing the power transmission coil device 4 is made of a non-magnetic material, for example, resin, a magnetic flux generated by the coil device 4 is not affected. Therefore, efficient wireless power transfer is achieved. Further, when a non-magnetic and non-conducting material is used for the protective cover 11, power efficiency of wireless power transfer may be further increased. When the base 12 facing the vehicle body side is made of a non-magnetic and conductive material, structural strength of the coil device 5 may be improved while suppressing an influence on a magnetic field distribution between the coil device 4 and the coil device 5. In addition, the non-magnetic and conductive base 12 functions as a magnetic shielding, and thus magnetic fluxes heading the coil devices 4 and 5 increase, and power efficiency may be improved.

In the above Patent Literature 2, an outer circumferential portion of the bobbin is attached to the vehicle, and thus a central region is not fixed. For this reason, there is concern that a central region may be easily bent and broken, thereby causing damage due to external impact even when the power reception coil device of Patent Literature 1 is attached as in Patent Literature 2. In addition, the power reception coil device is subjected to thermal strain due to power reception, or receives a vibration of the vehicle. The central region, which is not fixed, is easily affected by a force generated in these circumstances. In this regard, according to the coil device 5 of the present embodiment, strength of the central region of the housing 10 is increased, and the above-mentioned problem is solved.

The above Patent Literature 3 discloses that a central region of the substrate is bolted. However, only the substrate is fixed, and the protective cover is not fixed. For this reason, a central region of the protective cover is bent similarly to Patent Literature 2. In addition, Patent Literature 2 mentions a spacer for ensuring strength of the protective cover. However, when the power reception unit is attached backward, and the protective cover is bent, a gap is generated between the spacer and the protective cover. Thus, there is difficulty in ensuring strength of the protective cover. In this regard, in the coil device 5 of the present embodiment, the housing 10 and the bobbin 20 are fastened by the fastener 16, and thus strength of the housing 10 is ensured.

Originally, the bolt or the spacer may be provided in the central region of the power reception unit as in Patent Literature 3 since the coil has a circular shape in which a space is present in the central region. There is difficulty in employing a scheme of Patent Literature 3 in a solenoid coil as in Patent Literature 1 in which a conductive wire is wound around a central region. In addition, a cross-sectional view of the power reception coil device is given in FIG. 7 of Patent Literature 1, and conductive wire positions of an upper ferrite housing portion and a lower ferrite housing portion are matched with each other. Thus, the bolt may be vertically inserted so as not to interfere in the conductive wire. However, a pitch of the conductive wire may not be longer than a width of the bolt. As disclosed in Patent Literature 2 (paragraph 0025), when the conductive wire is sparsely and densely wound, there are problems of heating due to an eddy current in a dense part and a magnetic flux leakage in a sparse part, and thus the conductive wire is preferably wound at equal intervals. For this reason, when the pitch of the conductive wire is set to be wider than the width of the bolt, the power reception coil device increases in size as a whole. However, the power reception coil device is required to be reduced in size due to a characteristic that the power reception coil device is installed in a vehicle in which an installation position is restricted. In addition, the conductive wire needs to be densely wound to improve transmitting efficiency. For this reason, there is difficulty in setting all pitches of the conductive wire to be wider than the width of the bolt. Further, positions of the conductive wire are provided in a diagonal shape rather than being vertically matched in many cases in terms of ensuring an insulation distance (necessity of separating pieces of the conductive wire as much as possible) (see the surface-side extending portions 31 and the rear surface-side extending portions 32 illustrated in FIG. 14). In this case, one of upper and lower pitches of the conductive wire (a gap between the surface-side extending portions 31 and 31) includes another conductive wire position (the rear surface-side extending portion 32), and thus there is difficulty in inserting a bolt 116 such that the conductive wire is not interfered. In this regard, in the coil device 5 of the present embodiment, the above-mentioned various problems are overcome.

The present invention is not limited to the above-described embodiment. The present invention includes various modifications. In the above embodiment, a description has been given of a mode in which arrangement of the fastener 16 is determined based on the first central region A1 of the bobbin 20 or the second central region A2 of the housing 10. However, arrangement of the fastener 16 may be determined based on another criterion.

For example, as illustrated in FIG. 6A, arrangement of the fastener 16 may be determined based on a viewpoint on a magnetic flux. In the bobbin 20, regions FS and FS in which a magnetic flux is strong are formed at both end portions in the winding axis direction. Regions FM and FM in which a magnetic flux is moderate are formed at both end portions in the wound wire direction. A magnetic flux is relatively weak in a central region FW in the winding axis direction and the wound wire direction except for the region FS and the region FM. In some modes, one or a plurality of fasteners 16 may be disposed in the region FM in which the magnetic flux is weak.

A description will be given of a specific range of the region FW in which the magnetic flux is weak. The regions FS and FS in which the magnetic flux is strong are regions corresponding to 20% to 40% of a whole length of the coil portion C in the winding axis direction from both end portions of the coil portion C. The regions FM and FM in which the magnetic flux is moderate are regions corresponding to 20% to 40% of a whole length of the coil portion C in the wound wire direction from both end portions of the coil portion C. Therefore, for example, the region FW in which the magnetic flux is weak corresponds to a region in a range of 20% to 60% in the middle in the winding axis direction and a region in a range of 20% to 60% in the middle in the winding axis direction.

When a determination scheme based on the viewpoint on the magnetic flux is described from another point of view, the fastener 16 may be provided in a region in which a decrease in power efficiency due to provision of the fastener 16 is less than or equal to 0.1%. In this case, an influence on power efficiency by the fastener 16 may be made as small as possible. When the determination scheme based on the viewpoint on the magnetic flux is described from another different point of view, the fastener 16 may be provided in a region in which a magnetic flux density in the coil portion C is lower than that in another region. In this case, an influence on a magnetic flux by the fastener 16 may be made as small as possible. An average magnetic flux density in a plurality of regions may be calculated, and the fastener 16 may be provided in a region in which a magnetic flux density is lower than the average. The fastener 16 may be provided in a region in which a magnetic flux density is lowest.

As illustrated in FIG. 6B, arrangement of the fastener 16 may be determined based on a viewpoint on strength. In some modes, one or a plurality of fasteners 16 may be provided in a rectangular-shaped region A3 extending in a short-side direction of the bobbin 20 (that is, the winding axis direction) in which the intersection point of the first diagonal lines L1 and L1 of the bobbin 20 is set as a center.

As illustrated in FIG. 7, one or a plurality of fasteners 16 may be provided in a region A4 where the region FW in which the magnetic flux is weak overlaps the rectangular-shaped region A3.

As illustrated in FIG. 8, it is possible to employ a mode in which a fastener is divided into two parts corresponding to a fastener 16A on the protective cover 11 side and a fastener 16A on the base 12 side. The respective fasteners 16A and 16A are obliquely disposed with respect to the plane orthogonal to the winding axis direction. In this case, the two fasteners 16A and 16A are provided from the outside of the housing 10. The fastener 16A on the protective cover 11 side penetrates through the protective cover 11, and does not penetrate through the ferrite plate 23. The fastener 16A on the base 12 side penetrates through the base 12, and does not penetrate through the ferrite plate 23. In other words, a distal end of the fastener 16A terminates inside the first winding plate 21 or the second winding plate 22. A seal member is provided between the fastener 16A on the protective cover 11 side and the protective cover 11. A seal member is provided between the fastener 16A on the base 12 side and the base 12.

As illustrated in FIG. 9, it is possible to employ a mode in which a fastener is divided into two parts corresponding to a fastener 16B on the protective cover 11 side and a fastener 16B on the base 12 side. The respective fasteners 16B and 16B are obliquely disposed with respect to the plane orthogonal to the winding axis direction. In this case, the two fasteners 16B and 16B are provided from the inside of the bobbin 20 (that is, the ferrite plate 23 side of the first winding plate 21 and the ferrite plate 23 side of the second winding plate 22). The fastener 16B on the protective cover 11 side does not penetrate through the protective cover 11 and the ferrite plate 23. The fastener 16B on the base 12 side does not penetrate through the base 12 and the ferrite plate 23. In other words, a base end of the fastener 16B does not protrude from a surface of the first winding plate 21 or the second winding plate 22 on the ferrite plate 23 side. A distal end of the fastener 16B on the protective cover 11 side terminates inside the protective cover 11. A distal end of the fastener 16B on the base 12 side terminates inside the base 12. A seal member is not needed between the fastener 16B on the protective cover 11 side and the protective cover 11. A seal member is not needed between the fastener 16B on the base 12 side and the base 12.

As illustrated in FIG. 10, it is possible to employ a mode in which two fasteners 16C and 16C are provided on the protective cover 11 side. The respective fasteners 16C and 16C are obliquely disposed with respect to the plane orthogonal to the winding axis direction. The fasteners 16C and 16C penetrate through the protective cover 11 and the ferrite plate 23. Distal ends of the fasteners 16C and 16C terminate inside the base 12. Seal members are provided between the fasteners 16C and 16C and the protective cover 11.

As illustrated in FIG. 11, it is possible to employ a mode in which a plurality of miniaturized screw members is used. FIG. 11 illustrates a case in which four fasteners 16D are provided. Some (or all) of the plurality of fasteners 16D are obliquely disposed with respect to the plane orthogonal to the winding axis direction. A thickness (diameter) of each of the fasteners 16D may be appropriately changed. For example, one medium-sized fastener 16D is used on the protective cover 11 side to fasten the protective cover 11 and the first winding plate 21. The second winding plate 22 and the ferrite plate 23 are fastened by two small-sized fasteners 16D and 16D on the base 12 side. Further, the base 12 and the second winding plate 22 are fastened by one small-sized fastener 16D. A seal member is provided between the fastener 16D and the protective cover 11 or the base 12 only when the fastener 16D penetrates through the protective cover 11 or the base 12. The “middle-sized fastener” and the “small-sized fastener” correspond to thicknesses (diameters) when the one fastener 16 illustrated in FIG. 3A and FIG. 3B is set as a criterion. When a plurality of middle-sized or small-sized fasteners is used, an influence on a magnetic field distribution may be reduced.

As illustrated in FIG. 12, a key structure may be provided inside the protective cover 11 and the base 12. That is, a fastener 16E includes a first combined member 11 e integrally provided with a protective cover 11E to protrude toward a base 12E, and a second combined member 12 e integrally provided with the base 12E to protrude toward the protective cover 11E. At least one of the first combined member 11 e and the second combined member 12 e is disposed inside a coil portion CE. In other words, at least one of the first combined member 11 e and the second combined member 12 e intersects with (enters) the coil portion CE. The first combined member 11 e and the second combined member 12 e are combined together. The first combined member 11 e and the second combined member 12 e are obliquely disposed with respect to the plane orthogonal to the winding axis direction while being combined with each other. More specifically, the fastener 16E is configured such that a distal end of the first combined member 11 e fits into a depression of a distal end of the second combined member 12 e. As the protective cover 11E is further pressed against the base 12E, fastening strength between the first combined member 11 e and the second combined member 12 e increases. In this case, the fastener 16E is integrally provided with a housing 10E, and does not penetrate through the housing 10E, and thus a seal around the fastener 16E is not needed.

As illustrated in FIG. 13A, two (a plurality of) fasteners 16F may be arranged along the winding axis direction. In this case, the fasteners 16F and 16F may be provided in point symmetry about the intersection point of the first diagonal lines L1 and L1, that is, the central point of the bobbin 20 (see FIG. 5). In this way, loads applied to both the fasteners 16F and 16F may be easily balanced, and thus strength of the protective cover may be easily increased.

As illustrated in FIG. 13B, two (a plurality of) fasteners 16G may be arranged along the wound wire direction. In this case, the fasteners 16G and 16G may be provided in point symmetry about the intersection point of the first diagonal lines L1 and L1, that is, the central point of the bobbin 20 (see FIG. 5).

If one or a plurality of fasteners is provided as described above, a size of the fastener may be determined such that a surface area of a surface through which magnetic fluxes of the fastener pass is the same as a surface area obtained when one fastener 16 is provided. When a surface area of a surface through which magnetic fluxes pass is prevented from increasing, a demerit due to a plurality of fasteners is excluded. For example, the fasteners 16A to 16G may be disposed along a plane orthogonal to the wound wire direction. The plane orthogonal to the wound wire direction refers to a virtual plane that extends in the winding axis direction and the vertical direction (that is, the plate thickness direction of the first winding plate 21 and the second winding plate 22). In this case, with regard to the fasteners 16A to 16G, it is possible to minimize a surface area of a surface through which magnetic fluxes pass.

The present invention is not limited to a case in which a gap between the surface-side extending portions 31 and 31 is uniform in all portions on the first winding plate 21, and the gap between the surface-side extending portions 31 and 31 may be non-uniform in one portion. In this case, a pitch of some of the plurality of groove portions 21 b may be different from a pitch of other portions. The present invention is not limited to a case in which a gap between the rear surface-side extending portions 32 and 32 is uniform in all portions on the second winding plate 22, and the gap between the rear surface-side extending portions 32 and 32 may be non-uniform in one portion. In this case, a pitch of some of the plurality of groove portions 22 b may be different from a pitch of other portions.

A description has been given of a case in which the groove portions 21 b and the groove portions 22 b are formed on the first winding plate 21 and the second winding plate 22. However, the present invention is not limited to this case. The groove portions may not be formed on the winding plates, and the conductive wire 30 may extend on a surface of a flat winding plate. The distal end portion 17 c of the fastener 16 may penetrate through the base 12. That is, the distal end portion 17 c of the fastener 16 may protrude to the EV side. For example, the distal end portion 17 c penetrating through the base 12 is screwed to the vehicle body, and the coil device 5 is more strongly installed in the vehicle. Any member capable of fastening the bobbin and the housing may be used as the fastener, and a screw, a rivet, etc. may be used.

The present invention is not limited to a case in which the bobbin 20 is disposed on the base 12 such that the first central region A1 and the second central region A2 do not fully overlap each other (see FIG. 5). For example, the bobbin 20 may be disposed on the base 12 such that a center of the bobbin 20 overlaps a center of the base 12.

The above embodiment gives an example in which the litz wire is used as the conductive wire 30. However, the present invention is not limited thereto. A conductive wire other than the litz wire may be used as long as the conductive wire functions as a coil device for wireless power transfer. For example, a type, a figure, a form, a material, a configuration, a shape, and a dimension of the conductive wire 30 are arbitrarily selected.

In the above embodiment, a description has been given on a case in which the present disclosure is applied to the coil device 5. However, the present invention is not limited thereto. The present disclosure may be applied to the power transmission coil device 4. In addition, in the above embodiment, a description has been given on a case in which the coil device of the present disclosure is applied to the wireless power transfer system. However, a system to which the coil device is applied is not restricted to the wireless power transfer system. For example, the coil device of the present disclosure may be applied to an induction heating system or an eddy current flaw detection system.

INDUSTRIAL APPLICABILITY

According to some embodiments of the present disclosure, strength of a housing may be increased in a coil device of solenoid type. 

The invention claimed is:
 1. A coil device of solenoid type comprising: a coil portion having a bobbin and a conductive wire wound around the bobbin, and a magnetic member disposed inside the bobbin; a housing for accommodating the coil portion; and at least one fastener for fastening the bobbin, the housing and the magnetic member, wherein the conductive wire includes a plurality of extending portions extending along a wound wire direction, which intersects on the bobbin with a winding axis direction, and the at least one fastener is provided between the plurality of extending portions, and is obliquely disposed with respect to a plane orthogonal to the winding axis direction, and penetrates through the bobbin and the magnetic member, wherein the housing includes a first housing member facing a first surface of the coil portion having a flat plate shape, and a second housing member fixed to the first housing member to face a second surface on an opposite side from the first surface, and wherein the bobbin includes a first winding plate disposed between the first housing member and the magnetic member, and a second winding plate disposed between the second housing member and the magnetic member.
 2. The coil device according to claim 1, wherein the at least one fastener fastens the first winding plate and the second winding plate.
 3. The coil device according to claim 2, wherein a hole portion is provided in the magnetic member, one of the first winding plate and the second winding plate includes a protrusion protruding to an inside of the hole portion, and the at least one fastener penetrates through the protrusion to fasten the first winding plate and the second winding plate.
 4. The coil device according to claim 2, wherein the at least one fastener includes a flange portion contacting the first winding plate from a side of the first housing member, and the first housing member is supported by the coil portion through the flange portion.
 5. The coil device according to claim 1, wherein the at least one fastener penetrates through the housing.
 6. The coil device according to claim 1, wherein the at least one fastener includes a first combined member integrally provided in the first housing member to protrude toward the second housing member, and a second combined member integrally provided in the second housing member to protrude toward the first housing member, and at least one of the first combined member and the second combined member is disposed inside the coil portion, and the first combined member and the second combined member are combined together.
 7. The coil device according to claim 1, wherein the coil portion includes an equal portion in which a gap between extending portions adjacent to each other in the winding axis direction is equal to a gap between other extending portions, and the at least one fastener is provided in the equal portion.
 8. The coil device according to claim 1, wherein the at least one fastener is provided in a central region of the bobbin in the wound wire direction and the winding axis direction.
 9. The coil device according to claim 1, wherein the at least one fastener is provided in a central region of the housing in the wound wire direction and the winding axis direction.
 10. The coil device according to claim 1, wherein the at least one fastener is provided in a region in which a decrease in power efficiency due to provision of the fastener is less than or equal to 0.1%.
 11. The coil device according to claim 1, wherein the at least one fastener is provided in a region in which a magnetic flux density in the coil portion is lower than a magnetic flux density in another region.
 12. The coil device according to claim 1, wherein the at least one fastener comprises a plurality of fasteners, and the plurality of fasteners are arranged along the winding axis direction.
 13. The coil device according to claim 1, wherein the at least one fastener comprises a plurality of fasteners, and the plurality of fasteners are arranged along the wound wire direction. 